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The procps developers are happy to announce that version 3.3.12 of procps was released today. This version has a mixture of bug fixes and enhancements. This unfortunately means another API bump but we are hoping this will be fixed with the new library API coming soon.

I recently received Debian bug report #798350 where the user had a problem with wordpress. After upgrading to version 4.3, the webservers performance degrades over time. The problem is also reported at the wordpress site with bug WordPress ticket 33423 including the fix.

I have backported the relevant changeset and uploaded Debian wordpress package 4.3+dfsg-2 which only contains this changeset. For a lot of people, including myself, you probably won’t hit this bug but if it impacts you, then try this update.

I’m getting close to releasing version 3.3.11 of procps. When it gets near that time, I generally browse again the Debian Bug Tracker for procps bugs. Bug number #733758 caught my eye. With the free command if you used the s option before the c option, the s option failed, “seconds argument ‘N’ failed” where N was the number you typed in. The error should be for you trying to type letters for number of seconds. Seemed reasonably simple to test and simple to fix.

At first I thought the logic was wrong, but tracing through it was fine. I then compiled free using the upstream git source, the program worked fine with s flag with no c flag. Doing a diff between the upstream HEAD and Debian’s 3.3.10 source showed nothing obvious.

I then shifted the upstream git to 3.3.10 too and re-compiled. The Debian source failed, the upstream parsed the s flag fine. I ran diff, no change. I ran md5sum, the hashes matched; what is going on here?

I’ll set when I want

The man page says in the case of under/overflow “ERANGE is stored in errno”. What this means is if there isn’t and under/overflow then errno is NOT set to 0, but its just not set at all. This is quite useful when you have a chain of functions and you just want to know something failed, but don’t care what.

Most of the time, you generally would have a “Have I failed?” test and then check errno for why. A typical example is socket calls where anything less than 0 means failure. You check the return value first and then errno. strtof() is one of those funny ones where most people check errno directly; its simpler than checking for +/- HUGE_VAL. You can see though that there are traps.

What’s the difference?

OK, so a simple errno=0 above the call fixes it, but why would the Debian source tree have this failure and the upstream not? Even with the same code? The difference is how they are compiled.

It’s not the compiling of free itself that is doing it, but the library. Most likely something that is called before the strtof() is setting errno which this code then falls into. In fact if you run the upstream free linked to the Debian procps library it fails.

Moral of the story is to set errno before the function is called if you are going to depend on it for checking if the function succeeded.

I have previously written about the gitlab CI runners that use docker. Yesterday I made some changes to procps and pushed them to gitlab which would then start the CI. This morning I checked and it said build failed – ok, so that’s not terribly unusual. The output from the runner was:

For quite some time, the Debian version of WordPress has had a configuration tweak that made it possible to run multiple websites on the same server. This came from a while ago when multi-site wasn’t available. While a useful feature, it does make the initial setup of WordPress for simple sites more complicated.

I’m looking at changing the Debian package slightly so that for a single-site use it Just Works. I have also looked into the way WordPress handles the content, especially themes and plugins, to see if there is a way of updating them through the website itself. This probably won’t suit everyone but I think its a better default.